The Internet

How does the Internet work

  • The Internet is a collection of standalone computers all loosely linked together, mostly using the telephone network.
  • The Internet has one job - to move computerized information(data) from one place to another.

  • When two computers need to communicate, you have to link them, either physically(Ethernet) or wirelessly(WIFI, Bluetooth).
  • To connect many computers more easily, each computer on a network is connected to a special tiny computer called a router.
  • router - like a signaler at a railway station, makes sure that a message sent from a given computer arrives at the right destination computer.
    • By connecting computers to routers, then routers to routers, we are ale to scale infinitely.
  • To connect our network to the telephone infrastructure, we need a special piece of equipment called a modem.
    • This modem turns the information from our network into information manageable by the telephone infrastructure and vice versa.
  • To send the messages from our network to the network we want to reach, we will connect our network to an Internet Service Provider (ISP).
    • An ISP is a company that manages some special routers that link all together and can also access other ISPs’ routers. So the message from our network is carried through the network of ISP networks to the destination network.
  • Any computer linked to a network has a unique address to identify it, called an “IP address” (Internet Protocol).
  • To make things easier, we can alias an IP address with a human readable name called a domain name. ( is the domain name used on top of the IP address

  • The Internet is a technical infrastructure which allows billions of computers to be connected all together.
  • Among those computers, some computers (called Web servers) can send messages intelligible to web browsers.
  • The Internet is an infrastructure, whereas the Web is a service built on top of the infrastructure.